There have been many proposals over the years to propel water craft by means of an oar like arrangement with two flaps which are pivoted about an axis. A stop member is provided so that as the flaps move forwardly, the flaps are closed by their forward movement through the water. However when the flaps move rearwardly, the flaps open against the stop member and the large surface moving rearwardly through the water propels the watercraft forwardly. The following prior art specifications are representative of this art.                U.S. Pat. No. 817,810 (SHEEN-1906)        U.S. Pat. No. 1,204,937 (CARLEY-1916)        U.S. Pat. No. 1,324,397 (HOBART-1919)        U.S. Pat. No. 4,098,219 (TESAN)        U.S. Pat. No. 4,892,493 (GILL)        GB 992,948 (BECKETT)        CA 2,219,471A (BOYLAN)        DE 3,141,738A (BLUEGGEL)        
To the best of the applicant's knowledge, none of these proposals have been commercially successful and the general principle of propulsion has not been adopted as a practical proposition. This is thought to be due to the difficulty of successfully applying muscular energy to the pivoted flaps.
A different body of art in relation to water craft concerns the movement of such craft by means of reciprocating a fin like body which resembles the flukes of a whale or the oar used with Venetian gondolas. The following patent specifications are representative of this art.                U.S. Pat. No. 3,086,492 (HOLLEY)        U.S. Pat. No. 3,640,240 (STEIN)        U.S. Pat. No. 4,193,371 (BAULARD-CAUGAN)        U.S. Pat. No. 4,968,273 (MOMOT)        U.S. Pat. No. 6,595,813 (LEKHTMAN)        U.S. Pat. No. 6,755,706 (LIN)        GB 2,212,467A (WATKISS)        
Again, to the best of the applicant's knowledge, none of these proposals have been commercially successful nor has the general principle of propulsion been adopted as a practical proposition. This is thought to be due to the difficulty of moving a sufficient volume of water by the movement of the fin or fluke.
The genesis of the present invention is a desire to see each of these hitherto separate, and commercially unsuccessful, proposals combined so is to each ameliorate the other's difficulties.